#ifndef __Vector2_H__
#define __Vector2_H__


#include "Common.h"
/** Standard 2-dimensional vector.
		@remarks
			A direction in 2D space represented as distances along the 2
			orthogonal axes (x, y). Note that positions, directions and
			scaling factors can be represented by a vector, depending on how
			you interpret the values.
	*/
class  SERVER_DECL Vector2
{
public:
	Real x, y;

public:
	inline Vector2()
	{
	}

	inline Vector2(const Real fX, const Real fY )
	: x( fX ), y( fY )
	{
	}

	inline explicit Vector2( const Real scaler )
	: x( scaler), y( scaler )
	{
	}

	inline explicit Vector2( const Real afCoordinate[2] )
	: x( afCoordinate[0] ),
	y( afCoordinate[1] )
	{
	}

	inline explicit Vector2( const int afCoordinate[2] )
	{
		x = (Real)afCoordinate[0];
		y = (Real)afCoordinate[1];
	}

	inline explicit Vector2( Real* const r )
	: x( r[0] ), y( r[1] )
	{
	}

	inline Real operator [] ( const size_t i ) const
	{
		assert( i < 2 );

		return *(&x+i);
	}

	inline Real& operator [] ( const size_t i )
	{
		assert( i < 2 );

		return *(&x+i);
	}

	/// Pointer accessor for direct copying
	inline Real* ptr()
	{
		return &x;
	}
	/// Pointer accessor for direct copying
	inline const Real* ptr() const
	{
		return &x;
	}

	/** Assigns the value of the other vector.
			@param
				rkVector The other vector
		*/
	inline Vector2& operator = ( const Vector2& rkVector )
	{
		x = rkVector.x;
		y = rkVector.y;

		return *this;
	}

	inline Vector2& operator = ( const Real fScalar)
	{
		x = fScalar;
		y = fScalar;

		return *this;
	}

	inline bool operator == ( const Vector2& rkVector ) const
	{
		return ( x == rkVector.x && y == rkVector.y );
	}

	inline bool operator != ( const Vector2& rkVector ) const
	{
		return ( x != rkVector.x || y != rkVector.y  );
	}

	// arithmetic operations
	inline Vector2 operator + ( const Vector2& rkVector ) const
	{
		return Vector2(
		x + rkVector.x,
		y + rkVector.y);
	}

	inline Vector2 operator - ( const Vector2& rkVector ) const
	{
		return Vector2(
		x - rkVector.x,
		y - rkVector.y);
	}

	inline Vector2 operator * ( const Real fScalar ) const
	{
		return Vector2(
		x * fScalar,
		y * fScalar);
	}

	inline Vector2 operator * ( const Vector2& rhs) const
	{
		return Vector2(
		x * rhs.x,
		y * rhs.y);
	}

	inline Vector2 operator / ( const Real fScalar ) const
	{
		assert( fScalar != 0.0 );

		Real fInv = 1.0 / fScalar;

		return Vector2(
		x * fInv,
		y * fInv);
	}

	inline Vector2 operator / ( const Vector2& rhs) const
	{
		return Vector2(
		x / rhs.x,
		y / rhs.y);
	}

	inline const Vector2& operator + () const
	{
		return *this;
	}

	inline Vector2 operator - () const
	{
		return Vector2(-x, -y);
	}

	// overloaded operators to help Vector2
	inline friend Vector2 operator * ( const Real fScalar, const Vector2& rkVector )
	{
		return Vector2(
		fScalar * rkVector.x,
		fScalar * rkVector.y);
	}

	inline friend Vector2 operator / ( const Real fScalar, const Vector2& rkVector )
	{
		return Vector2(
		fScalar / rkVector.x,
		fScalar / rkVector.y);
	}

	inline friend Vector2 operator + (const Vector2& lhs, const Real rhs)
	{
		return Vector2(
		lhs.x + rhs,
		lhs.y + rhs);
	}

	inline friend Vector2 operator + (const Real lhs, const Vector2& rhs)
	{
		return Vector2(
		lhs + rhs.x,
		lhs + rhs.y);
	}

	inline friend Vector2 operator - (const Vector2& lhs, const Real rhs)
	{
		return Vector2(
		lhs.x - rhs,
		lhs.y - rhs);
	}

	inline friend Vector2 operator - (const Real lhs, const Vector2& rhs)
	{
		return Vector2(
		lhs - rhs.x,
		lhs - rhs.y);
	}
	// arithmetic updates
	inline Vector2& operator += ( const Vector2& rkVector )
	{
		x += rkVector.x;
		y += rkVector.y;

		return *this;
	}

	inline Vector2& operator += ( const Real fScaler )
	{
		x += fScaler;
		y += fScaler;

		return *this;
	}

	inline Vector2& operator -= ( const Vector2& rkVector )
	{
		x -= rkVector.x;
		y -= rkVector.y;

		return *this;
	}

	inline Vector2& operator -= ( const Real fScaler )
	{
		x -= fScaler;
		y -= fScaler;

		return *this;
	}

	inline Vector2& operator *= ( const Real fScalar )
	{
		x *= fScalar;
		y *= fScalar;

		return *this;
	}

	inline Vector2& operator *= ( const Vector2& rkVector )
	{
		x *= rkVector.x;
		y *= rkVector.y;

		return *this;
	}

	inline Vector2& operator /= ( const Real fScalar )
	{
		assert( fScalar != 0.0 );

		Real fInv = 1.0 / fScalar;

		x *= fInv;
		y *= fInv;

		return *this;
	}

	inline Vector2& operator /= ( const Vector2& rkVector )
	{
		x /= rkVector.x;
		y /= rkVector.y;

		return *this;
	}

	/** Returns the length (magnitude) of the vector.
			@warning
				This operation requires a square root and is expensive in
				terms of CPU operations. If you don't need to know the exact
				length (e.g. for just comparing lengths) use squaredLength()
				instead.
		*/
	inline Real length () const
	{
		return (Real) sqrt( x * x + y * y );
	}

	/** Returns the square of the length(magnitude) of the vector.
			@remarks
				This  method is for efficiency - calculating the actual
				length of a vector requires a square root, which is expensive
				in terms of the operations required. This method returns the
				square of the length of the vector, i.e. the same as the
				length but before the square root is taken. Use this if you
				want to find the longest / shortest vector without incurring
				the square root.
		*/
	inline Real squaredLength () const
	{
		return x * x + y * y;
	}

	/** Calculates the dot (scalar) product of this vector with another.
			@remarks
				The dot product can be used to calculate the angle between 2
				vectors. If both are unit vectors, the dot product is the
				cosine of the angle; otherwise the dot product must be
				divided by the product of the lengths of both vectors to get
				the cosine of the angle. This result can further be used to
				calculate the distance of a point from a plane.
			@param
				vec Vector with which to calculate the dot product (together
				with this one).
			@returns
				A float representing the dot product value.
		*/
	inline Real dotProduct(const Vector2& vec) const
	{
		return x * vec.x + y * vec.y;
	}

	/** Normalises the vector.
			@remarks
				This method normalises the vector such that it's
				length / magnitude is 1. The result is called a unit vector.
			@note
				This function will not crash for zero-sized vectors, but there
				will be no changes made to their components.
			@returns The previous length of the vector.
		*/
	inline Real normalise()
	{
		Real fLength = (Real) sqrt( x * x + y * y);

		// Will also work for zero-sized vectors, but will change nothing
		if ( fLength > 1e-08 )
		{
			Real fInvLength = 1.0 / fLength;
			x *= fInvLength;
			y *= fInvLength;
		}

		return fLength;
	}



	/** Returns a vector at a point half way between this and the passed
			in vector.
		*/
	inline Vector2 midPoint( const Vector2& vec ) const
	{
		return Vector2(
		( x + vec.x ) * 0.5,
		( y + vec.y ) * 0.5 );
	}

	/** Returns true if the vector's scalar components are all greater
			that the ones of the vector it is compared against.
		*/
	inline bool operator < ( const Vector2& rhs ) const
	{
		if( x < rhs.x && y < rhs.y )
		return true;
		return false;
	}

	/** Returns true if the vector's scalar components are all smaller
			that the ones of the vector it is compared against.
		*/
	inline bool operator > ( const Vector2& rhs ) const
	{
		if( x > rhs.x && y > rhs.y )
		return true;
		return false;
	}

	/** Sets this vector's components to the minimum of its own and the
			ones of the passed in vector.
			@remarks
				'Minimum' in this case means the combination of the lowest
				value of x, y and z from both vectors. Lowest is taken just
				numerically, not magnitude, so -1 < 0.
		*/
	inline void makeFloor( const Vector2& cmp )
	{
		if( cmp.x < x ) x = cmp.x;
		if( cmp.y < y ) y = cmp.y;
	}

	/** Sets this vector's components to the maximum of its own and the
			ones of the passed in vector.
			@remarks
				'Maximum' in this case means the combination of the highest
				value of x, y and z from both vectors. Highest is taken just
				numerically, not magnitude, so 1 > -3.
		*/
	inline void makeCeil( const Vector2& cmp )
	{
		if( cmp.x > x ) x = cmp.x;
		if( cmp.y > y ) y = cmp.y;
	}

	/** Generates a vector perpendicular to this vector (eg an 'up' vector).
			@remarks
				This method will return a vector which is perpendicular to this
				vector. There are an infinite number of possibilities but this
				method will guarantee to generate one of them. If you need more
				control you should use the Quaternion class.
		*/
	inline Vector2 perpendicular(void) const
	{
		return Vector2 (-y, x);
	}
	/** Calculates the 2 dimensional cross-product of 2 vectors, which results
			in a single floating point value which is 2 times the area of the triangle.
		*/
	inline Real crossProduct( const Vector2& rkVector ) const
	{
		return x * rkVector.y - y * rkVector.x;
	}

	/** Returns true if this vector is zero length. */
	inline bool isZeroLength(void) const
	{
		Real sqlen = (x * x) + (y * y);
		return (sqlen < (1e-06 * 1e-06));

	}

	/** As normalise, except that this vector is unaffected and the
			normalised vector is returned as a copy. */
	inline Vector2 normalisedCopy(void) const
	{
		Vector2 ret = *this;
		ret.normalise();
		return ret;
	}

	/** Calculates a reflection vector to the plane with the given normal .
		@remarks NB assumes 'this' is pointing AWAY FROM the plane, invert if it is not.
		*/
	inline Vector2 reflect(const Vector2& normal) const
	{
		return Vector2( *this - ( 2 * this->dotProduct(normal) * normal ) );
	}

	// special points
	static const Vector2 ZERO;
	static const Vector2 UNIT_X;
	static const Vector2 UNIT_Y;
	static const Vector2 NEGATIVE_UNIT_X;
	static const Vector2 NEGATIVE_UNIT_Y;
	static const Vector2 UNIT_SCALE;
};

#endif
